1. Field of the Invention
The present invention relates to a phosphor having composite oxynitride host crystal, efficiently excited in an ultraviolet to near ultraviolet wavelength region, and emitting high-brightness blue light, a method for producing the same, and a luminescent device using the same.
2. Description of the Related Art
Phosphors emit visible light when being excited by a high-energy excitation source such as vacuum ultraviolet light, ultraviolet light, electron beam, and near ultraviolet light. If phosphors are exposed to an excitation source for a long time, their brightness decreases, which is why a phosphor exhibiting little decrease in brightness even after a long period of use has been required.
To solve the above problem, oxynitride-based phosphors have been proposed, instead of conventional oxide-based phosphors such as silicate, phosphate, and aluminate phosphors, and sulfide-based phosphors (Patent Literatures 1 to 3) because the oxynitride-based materials are high in chemical stability and thus known as heat-resistant structural materials.